1. Field of the Invention
The present invention relates to a medical instrument. More particularly, the present invention relates to an improved laryngeal mask airway (LMA).
2. Description of the Related Art
In the case of anesthesia and apnea patients, the top priority is the provision of pulmonary gas by emergency medical personnel. Among the various respiration sustaining instruments, the LMA, due to its ease of operability, is a common alternative to endrotracheal intubation.
Please refer to FIG. 1 for the structure of a conventional LMA 10P. Basically, the LMA 10P comprises a flexible tubular portion 11P, an inflatable sealing cuff 13P, and an inflation tube 15P. The flexible tubular portion 11P comprises a first opening part 111P and a second opening part 112P. The inflatable sealing cuff 13P is disposed surrounding the first opening part 111P. The inflation tube 15P has one end connected to the inflatable sealing cuff 13P and the other end directing gas into the inflatable sealing cuff 13P.
Please refer to FIGS. 2 to 4 for illustrative diagrams showing the conventional laryngeal mask 10P in use. First, a user may insert the LMA 10P into a patient's mouth by the end having the inflatable sealing cuff 13P, which is in a deflated condition. When the inflatable sealing cuff 13P reaches a deeper part of the mouth, the user will then have to insert his/her finger into the patient's mouth to bend the front end of the LMA 10P to make the structure of the LMA 10P conform with the structure of the patient's upper jaw. In addition, due to the softness of the LMA 10P, the user may not exert force thereby. Thus, the user has to push aside the tongue with his/her finger to bend the first opening part 111P and the flexible tubular portion 11P to such an extent that they can reach past the upper jaw to the opening of the trachea, as shown in FIG. 3. In FIG. 4, when the LMA 10P gets to a specific position, the user may then aerate the inflatable sealing cuff 13P from the inflation tube 15P so as to form a sealing mask in the patient's throat. The sealing mask may encompass the opening of the trachea and form an air passage thereby. After that, the user may direct gas, such as oxygen, from the second opening part 112P to maintain the patient's respiration.
Accordingly, during the installation of an LMA 10P, users always have to insert their finger(s) (especially their index fingers) into a patient's mouth to pass the soft, inconvenient LMA 10P through the upper jaw because of the obstruction of the patient's tongue. In general, this displacement by fingers may cause two problems. First, there is the risk that the user may be bitten by the patient during the installation of an LMA 10P. Second, in a case where a patient's oral space is overly small, which may be caused by an overly small mouth, an overly tight tooth joint, or an overly thick tongue, a user may encounter difficulty inserting his/her finger(s) into the patient's mouth, resulting in failure to install the LMA 10P.
In addition to the LMA 10P mentioned above, an LMA with a gastric access tube has also been disclosed in the pertinent art, such as the one disclosed in U.S. Pat. No. 5,241,956. The major function of the gastric access tube is that it that allows for easy passage of a gastric tube or can serve as an escape conduit for regurgitant fluid, thus preventing aspiration and pulmonary contamination.